Coupling device



Aug. 21, 1934; w, R LEAR 1,971,315

COUPLING DEVICE Filed June 25, 1931 3 Sheets-Sheet 1 [Tu/6222 07 z'czmPLecu W. P. LEAR COUPLING DEVICE Aug. 21, 1934.

:5 Sheets-Sheet Filed June 25, 1931 ZMz'ZZz'am Fleur Aug. 21, 1934. w.P. LEAR 1,971,315

' COUPLING DEVICE Filed June 25, 1931 5 Sheets-Sheet I5 Q frzz/erzzf'William .PLear Patented Aug. 21, 1934 UNITED STATES 1.911.315 .conrunc.nnvlcs William P. Lear, Chicago, 111., assignor, by mesne assignments,to Meissner Manufacturing Company, Chicago, Ill.

Application June 25, 1931, Serial No. 546,815 3' Claims. (01. 175-356)My invention relates to an electrical coupling device for radioapparatus and more particularly to ,a coupling device for a tunedintermediate frequency amplifier as used in superheterodyne receivers.

The use of shielding containers for intermediate frequency transformerscauses energy losses in'the circuit and reduces the impedance of thetransformer coils. This is objectionable and re 1. quires thatadditional impedance be added to the coils and that the containers bemade large to space them farther from the coils.

These difliculties are overcome in the present invention by so relatingthe axes of the coils to 5 each other as to permit them to be closelyspaced and so positioning the axes of the coils with respect to the axesof the container as to reduce the losses in the container to a minimumthereby increasing the eflective impedance of the coils 0 and allowingthem to be made of relatively smaller size.

An object of thetinvention is to provide a new i and improved couplingdevice.

A further object is to provide a coupling transformer in which the axesof the coils are so dis posed as to allow the coils to be in closespatial relation.

A further object is to provide a shielding container for the transformercausing low loss of energy from the transformer.

A further object is to provide a coupling transformer device forproviding high amplification and selectivity.

Other objects and advantages will-appear as the description proceeds.

Referring to the drawings: Fig. 1 is a side elevation of a couplingdevice embodying my invention,

Fig. 2 is a view of the device shown in Fig. 1 rotated through an angleof 90 degrees,

Fig. 3 is a plan view of the device, Fig. 4 is a bottom view of thedevice, Fig. 5 is a schematic detail view of the condenser of saiddevice, Fig. 6 is a side elevation of a modified form of the invention,

Fig. '"l is a detail view of a further modification,

3 is a fragmentary view showing a modification in the mounting of thedevice,

9 is a circuit diagram showing the device as connected in a radiocircuit,

10 is a side elevation of a modified form of mounting for the'couplingdevice, K Fig. his a longitudinal section taken on line 11 of Fig. 10,and

Fig. 12 is a cross section taken on line 1212 of Fig. '10. Referring nowmore in detail to the drawings: a base 11 of any suitable insulatingmaterial is provided for supporting the coupling device. Extendingupwardly from the base is a forked support 12 having a pair of parallelarms for supporting coils 13 and 14. On either side of the support 12and secured to the base is a; condenser 15 which has a straight sidelying along the support and parallel therewith and a semi-circular sidewhich conforms to the contour of the base. Each of these condensers, asmay be more clearly seen in Fig. 5 consists of a condenser plate 16secured to the base, a second condenser plate 17 separated fromcondenser plate 16 by a sheet of dielectric material 18 and a flexiblecondenser plate 19 separated from condenser plate 17 by. a sheet ofdielectric material 21. The plates 16 and 19 are interconnected by atubular rivet 22 extending throughthe base and form in eflect a singleplate of thecondenser. The capacity of this condenser may be varied byad- Justing the position of plate 19 by means of a bolt 23 which extendsthrough the base and has 30 a slotted head 24 underneath the base sothat the capacity of the condenser may be changed from underneath thebase. The plate 17 forming the second plate of the condenser has adownwardly projecting lug 25 for making electrical 8 contact with thisplate of the condenser. Each of the condenser plates 1'1 also has anupstanding lug 26 to which the support 12 is attached.

The coils 13 and 14 are wound on a cylindrical core 27 of wood or othersuitable insulating material and each of these cores is provided ondiagonally opposite edges with a slot or groove so that the core fltsslidably between the arms of support 12. Both of the cores of the twocoils are identical, but by reversing the cores they may be so placedbetween the arms ofthe support that the axes of the coils are notparallel. However, the axis of each coil is perpendicular to the arms ofthe support.

One of the chief difliculties encountered in obtaining the propercharacteristics for the coils of an intermediate frequency transformeris to obtain a sufficiently high impedance of the coils. when the coilsare wound one upon the other, the impedance of the coils cannot beincreased beyond a given value because by adding additional turns thecapacity between the coils is also increased, to ofiset the effect ofadditional turns. For this reason the coils are separately wound into anannulus having a large number of turns,

the cross-section or Litz wire. turns in the coils, cure be taken not tohove 1e coils preieruhly he 0 rectangular. lit cl found thut the resultsare obtuine the coils are wcuuicl oi stranded wire commonly mourn asLitzendrah' or 0n account of the large munher of the coils may be veryclosely placed, in some cases having their peripheries in contact. Inadjusting the mutual inductance between the coils the lower coil i l isfirst placed between the arm. the support and secured in position byplacii small amount oi-sealing war: between the o and the arms of thesupport. The upp i is then adjusted until the proper che of thetransformer are obtained and ti then also secured to the urms oi thesupp means oi? sealing won or other suitable between the core and thearms. liluch oi the leads from one or the transformer coils c nected inparallel to one oi the condensers shown in Fig. 9, and four terminalleads, fill, 31 and 32 are brought out through the base so thatconnection may be conveniently made to the coupling device constitutedby the coils and the transformers. In order to mount the cou-- plingdevice on ,a flat surface such as the top of radio chassis, a pair of Ushaped clamps 33: ere secured to the base and these clamps or feet aresecured to a mounting surface by means of screws 34. In order tomagnetically and electrostatically shield the coupling device, ametallic container 35 having an open end is placed over the coils andbase, and secured to the feet 33 by means oi screws 36. On account ofthe circular outline formed by condensers 15 the maximum capacity" maybe obtained for the condensers within the available space upon the baseand within the container. It will be noted that the axes 01' the coilsare perpendicular to the axis 01 the container. By this arrangement theopen end or the can is placed in the path currents which tend to be setup in the can by the transformer coils so that a. minimum amount ofenergy will be wasted through eddy current losses in the container andconsequently the effective Impedance 01' the coils for a glven size willbe higher which is an impor-- tant feature.

Fig. d'shows a. modified form of the invention which is inprinciplesimilar to the form shown in Figs. l'to 5 except that the base11' is inverted in the container and adjacent the closed end there- 01'.The container is provided with apertures 37 through which the adjustingscrews 23' of the condensers may be reached to adjust the capacitythereof. This is in many cases the most convenient arrangement becausewhen the coritainer'35' is mounted upon the chassis, it is frequentlyinconvenlent to reach the screws for adjusting the capacity of thetransformers.

Fig. 'I shows a further modification in which a support 38 tor the coilsis provided with arms 39 and 41. The arm 41 is made wide enough so thata grid condenser 42, grid leak 43 may be mounted on the arm; Thisconstruction may be conveniently used in the coupling device precedingthe detector stage and shortens the leads from. the

the screen grid type is shown having a primary ii of the transformercoils in its anode circuit. The coil. 14 is connected through leads 139and ill to unother audion which may an amplifier detector audlon. Thedisposition and conthe inlotion oi the coils accordance "ion makes itpossible to cl.

-.l inductance between peaking of the resonance l ntc inventionemployirul: u lurked or support or" bake-lite, hard. rubber or heinoldable material. Referring to is shown having a support 62 mountedthereon. This support consists of a pair of arms 63 and 64. lilielowerportion of the arms consists of a substuntially rectangular pillar 65interconnected hy on it shaped connecting member 66. A flange ll'leutendc upwardly from each of the pillars to the top or the arm. On theinside oi the arm are inwardly extending flanges 68 which are providedwith a plurality of serrations which fit into the grooves in cores 69.In positioning the cores 69 of the coils between the arms the coils arepooltloncd as described in connection with Fig. 1 and a small quantityof sealing wax is then placed in the serrations to form a more effectivesupport for the coils on the arms. Each 01' the pillars 65 is providedwith an aperture '71 for securing the support to base 61 by means oiscrews 72 which pass through the bosom other support into the threadedapertures in the pillars 65. In this manner the U shaped or forkedsupport is securely mounted on the base. The support is further securedto the base by the upwardly extending projections '73 formed on thecondenser mounted on the base as described in connection with Fig. 1. Inorder to secure the shielding container 74 in position over thetransformer the U shaped support is provided with a plurality ofthreaded apertures 75 which receive screw! passing through the containerto rigidly pofltion the container on the support. These apertures 75 arecountersunk as shown and the countersunk portions may have pegs insertedtherein for supporting a shielding can when a larger size shield is usedthan shown. The upper ends of the modification shown in Fig. 6. when thesup- 141 port is inverted in the container the apertures 77 serve insecuring the support to a base which may be the top of a radio chassisor any other suitable base. Thls'iorm or support for the transformercoils forms a rugged and economical iii support and securely maintainsall of the parts in their proper spatial relationship.

It will be understood that the nature and embodiment of the inventionherein described and illustrated are merely convenient and useful formsof the invention and that many changes and modifications may be madetherein without departing from the spirit and scope of the invention.

What I claim is new and desire to protect by Letters Patent of theUnited States is:--

l. A coupling device comprising a pair of loosely coupled annular coils,a pair of substantially parallel arms for supporting the coilstherebetween, the axes of said coils being at an angle to the planeincluding said arms.

2. A coupling device comprising a base, a pair of substantially parallelarms mounted thereon, a pair of coils, each of said coils being wound ona cylindrical support, said supports having grooves for slidablyengaging said arms, and means for retaining said supports in position onsaid arms.

3. A coupling device comprising a base, a pair oi substantially parallelarms mounted thereon, a pair of coils mounted therebetween, the axes oisaid coils being perpendicular to said arms, and at an angle to eachother, whereby the coupling between said coils is reduced to permitclose spacing of the coils.

l. A coupling device comprising a base, arms extending perpendicularlyfrom said base, a pair oi? coils supported by said arms having theiraxes perpendicular to said arms and a metallic container on said baseenclosing said coils, the axis of said container being substantiallyperpendicular to the axis of said coils.

5. A coupling device comprising a base, a support extending upwardlytherefrom, a pair of transformer coils mounted on said support, a. pairof U shaped feet attached to said base to secure the device to a flatsurface and a metallic container enclosing said coils and secured tosaid feet.

6. A coupling device comprising a pair of annular coils wound ofstandard wire, means for mounting said coils including a pair ofsubstanti'ally parallel arms, the axes of said coils-being perpendicularto said arms and non-parallel to each other. I 7. A coupling devicecomprising a pair of annular coils having their axes in parallel planesbut relatively angularly disposed and with one coil positioned directlyabove the other so that the plane or the axis of one coil is above theplane of the axis of the other coil, and means for mounting the coils insaid position.

8. A coupling device comprising a pair of annular coils having theiraxes in parallel planes but relatively angularly disposed and with onecoil positioned directly above the other so that the plane of the axisof one coil is above the plane of the axis of the other coil and atubular shielding container positioned over the coils, the axis of saidcontainer being at right angle to the common plane of the axes of thecoils to reduce the energy loss in the container and increase theimpedance of,tlie coils.

" WILLIAM P. LEAR.

